98 INSECT LIFE. 



swiftly flying insects, as the bees, wasps, hawk-raoths, 

 and others, the hind wings are reduced in size, and 

 thus there is a concentration of the powers of flight 

 to a region near the front end of the body, which 

 adds to its efficiency, for the opposite arrangement 

 would result like an effort to shoot an arrow with the 

 wrong end forward ; with dragon-flies the hind wings 

 are as large as or larger than the fore wings, but 

 the great length of the abdomen results in the flight 

 organs as a whole being comparatively near the front 

 end of the body. It should also be observed that 

 the form of the abdomen is well fitted for the pecul- 

 iar method of laying the eggs. In the males of 

 dragon-flies there is a slit in the lower side of the 

 second abdominal segment, which contains an organ 

 furnished with hooks. Dragon-flies and damsel-flies 

 difl^er from all other insects in the position of this 

 organ of the males. Determine the sex of each of 

 your specimens and label them male or female as the 

 case may be. 



13. Make a sketch of the dragon-fly seen from 

 above. 



The Structure of Damsel-flies {School Work\ 

 — Compare the structure of a damsel-fly with that of 

 the dragon-fly already studied. Note especially the 

 form of the head with the eyes projecting like the 

 oarlocks of an outrigged skiff, the shape of the wings, 

 the position of the wings when at rest, and the form 

 of the ovipositor of the females. Make a sketch of 

 the head seen from above. Make a sketch showing 

 the outline of each of the wings of one side. Deter- 

 mine the sex of each of your specimens and label 

 them. 



